textproduct: Quad Cities

KEY MESSAGES

- Several cold fronts pushing down across the region will make for seasonally cooler air across the area for much of the week ahead with highs in the 70s to low 80s, and lows in 50s to low 60s.

- Scattered light showers and isolated thunderstorms are likely early Tuesday morning, with accumulations less than 0.10 inches expected.

- A seasonably strong system will bring the potential for severe thunderstorms on Wednesday. An Enhanced (Level 3 of 5) risk of severe thunderstorms is in effect for areas south of Highway 34, with the remainder of the area under a Slight (Level 2 of 5) risk.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 249 AM CDT Mon Jun 15 2026

Current water vapor imagery shows a shortwave trough moving across central Iowa. Further upstream, a second shortwave can be seen over the Pacific Northwest. Together, these waves will shape much of the short term forecast. The first wave, which is expected to move through eastern Iowa and northwest Illinois by 7 AM today, will provide a reinforcing push of cool and dry air to the area. Following its passage, today is expected to be cool and dry once again as we sit on the northern edge of high pressure centered over southern Missouri and Kansas. Expect highs in the mid to upper 70s and light westerly winds with gusts up to 20 mph.

Tonight, lows will fall into the mid 50s as the second shortwave, currently over the PNW, pushes into the area late tonight (around 4 AM) with a cold front. This will allow for scattered showers and a low (20-30%) chance of isolated thunderstorms in the 3 - 9 AM timeframe Tuesday morning, though there remains the question of moisture return. Guidance shows a plume of moisture ahead of the shortwave in ND/MN, with additional moisture circulating around the high pressure over MO/KS. Northwesterly flow keeps this moisture from entering the CWA, instead pushing it to the south and east. As a result, forcing along the cold front will have limited moisture, with the highest accumulations in northeast Missouri and northwest Illinois. NBM probabilities show a 70-85% chance of less than 0.10 inches of rain, and some areas, especially across eastern Iowa, may see no rain. Following frontal passage, Tuesday will be similar to today with highs in the mid to upper 70s, with the main difference being winds from the northwest and slightly more breezy.

LONG TERM /WEDNESDAY THROUGH SUNDAY/

Issued at 249 AM CDT Mon Jun 15 2026

The main story in the long term is a dynamically strong system forecast for Wednesday. Aloft, a shortwave coupled with a seasonably strong 500 mb jet of 65+ kts will move into the region. This, combined with a strong 850 mb jet, will provide a high shear environment with over 60 kts of bulk shear. Ahead of this shortwave, southerly flow is expected to increase. This will support moisture return overnight through Wednesday morning, with guidance suggesting PWATs of 1.5 - 2.0 moving into the area. On top of this highly sheared and moist environment, mid-level lapse rates of 8+ degC/km suggest the potential for a dynamically charged and unstable environment supportive of severe thunderstorms. As a result, SPC has an Enhanced (Level 3 of 5) risk of severe storms for areas south of Highway 34, with the remainder of the area under a Slight (Level 2 of 5) risk.

However, some uncertainty could limit the severe potential. The most likely limiter to severe potential is the moisture return. While the models suggest a large pool of moisture available across the region, the shortwave shifting latitude or speeding up/slowing down could limit how much moisture makes it into the area. Guidance agrees largely on the track of the surface low moving across central Minnesota, with a few pulling it further south along the Iowa- Minnesota border. With this track, if the system were to speed up, the axis of greatest moisture would tilt eastward, leaving the greatest moisture to our south. Additional areas of uncertainty, including potential for convection earlier in the day, will become more apparent as we approach Wednesday.

Past Wednesday, the forecast looks to be calmer as we return to the background northwesterly flow behind the departing system. High pressure will slide in Thursday from the northwest, interrupted briefly by a shortwave that could bring our next round of rain Thursday into Friday if we have ample moisture return. Otherwise, we will remain under the influence of high pressure through the weekend.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 537 AM CDT Mon Jun 15 2026

Clear skies and light winds will gradually see an increase and switch to the west today. Tonight, increasing southwest winds are anticipated, with some surface wind gusts expected near 20 kts. Northeast Iowa will see a period of LLWS towards morning, as winds blow from the west southwest at 40kts 2kft up. That period should end shortly after sunrise Tuesday. A few showers could spread in, but low coverage ( <20%) is expected at the surface, with mainly virga expected.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.